The character that I'm most interested in being added is Shantae, even though I'm 99.999% sure she'll never be added. I just think she has such potential for an awesome, unique moveset with all of the transformations and even the pirate weapons from The Pirate's Curse.
I'd love to see them add Rillaboom since Grass is my favorite Pokémon type and because it's the only of the Fire/Grass/Water starter trio that doesn't have at least one final evolution on the roster. I like Ivysaur and all, but I want more, you know? I very much don't see this happening either, if it's any Pokémon then it would probably be Cinderace. If it wasn't Decidueye's time last time, I unfortunately don't think it will be Rillaboom's time either. Maybe someday Grass will get some love.
A Mortal Kombat representative like Scorpion would be nice since we have Street Fighter and King of Fighters, but they'd have to figure out a way to balance being true to Mortal Kombat without being over the top violence since there'd be no Fatalities.
Waluigi would be fun, but he's already an Assist Trophy and I don't see them ever giving him more than that.
This probably won't happen either, but the protagonist from DOOM would be fun. I mean, there were so many memes about Doomguy and Isabelle.
Nintendo tweeted out this morning about a new fighter announcement that will be occurring tomorrow! Who are you guys hoping it will be? Personally I'm still holding out hope for.. Hector from FE7. But that's a long shot.
I'd love this too, but whether it's Intelligent Systems or Sakurai calling the shots, I don't see them pulling themselves out of the blue haired anime
swordfighter hole they've fallen in. I would absolutely love an axe user like Hector or a lance user like Ephraim but I've kind of given up hope. Heck, I'd love to see a Thief/Assassin like Volke or Jaffar, or a laguz like Ranulf, Tibarn or Naesala. A pure magical unit like Soren, Micaiah or Lysithea. Give us one of the villains, like Gharnef or Arvis or, since he's already in the series as an Assist Trophy, give us The Black Knight as a real heavy, heavy hitting swordy if we
have to have swords. Just give us something to represent more of the series,
please.
Regardless, with all of the salt from Byleth's release, I'd rather the series lie low until the next game.
---
Since I don't foresee anyone who I'm personally interested in being added, I'll be content with just about anybody they give us...except for Sora from Kingdom Hearts, since I really dislike that series for a few reasons. Even then though, it's just not my cup of tea and other people love it, so I'd be happy for those fans at least. It'd just be one character I wouldn't use among a roster of over 80 other characters.
Hopefully whoever it is will be fun to use and people enjoy them.